There is actually information under the blue artifact (If you cannot tell by the low quality animation) which makes me wonder how this could happen? (And who's head should roll?)
As this is a film school project, I don't have any contact with the lab myself, but they told the teachers it was because the camera wasn't clean.

It looks like an emulsion scratch (the top layer is the blue layer). Could be the loop in the camera being way too large, or a problem in a processing machine (only if sprocket drive). Did you hear any unusual noise during the shoot?

It looks like an emulsion scratch (the top layer is the blue layer). Could be the loop in the camera being way too large, or a problem in a processing machine (only if sprocket drive). Did you hear any unusual noise during the shoot?

Thanks for all your answers. We had a decent blimp on the camera, an Arri sr3, so we didn't hear anything funky from the camera. Though the previous roll jammed at 97 meters. There were 6 other groups before ours and one group after without any problems, so I don't think it's the camera. A too long loop is also what I might think could've happen